9,9-di-substituted -6,7-benzomorphans

ABSTRACT

6,7-BENZOMORPHAN DERIVATIVES HAVING ANALGESIC AND MORPHINEANTAGONISTIC PROPERTIES ARE OF THE FORMULA   IN WHICH THE SUBSTITUENTS R are either lower alkyl groups or groups which, together with the carbon atom to which they are bonded, form a cycloaliphatic ring, and the substituents R1, R2 and R3 may or may not be made and, if made, R1 represents either a hydrogen atom or an alkyl, haloalkyl, alkenyl, alkinyl, aralkyl, cycloalkenyl, cycloalkylalkyl, cycloalkenylalkyl or cycloalkylidine-alkyl group, R2 is an alkyl, aryl, heteroaryl or aralkyl group, and R3 is a hydrogen atom or an hydroxy, alkoxy, alkoxy-alkoxy or acyloxy group. Such 6,7-benzomorphans may be in the form of their optically active enantiomers and/or their therapeutically acceptable salts. There are also disclosed methods for producing such 6,7-benzomorphan derivatives, and intermediates useful in such production.

United States Patent [1 1 Akkerman et al.

[ 9,9-DI-SUBSTITUTED -6,7-BENZOMORPHANS [75] Inventors: Antony M. Akkerman, Amsterdam,

Netherlands; Paul Adriaan Jan ,lanssen, Vosselaar, Belgium [73] Assignee: ACF Chemiefarma N.V., Amsterdam, Netherlands 221 Filed: May 27,1910

211 Appl. No.: 41,079

[30] Foreign Application Priority Data June 4, 1969 Netherlands 6908527 June 4, 1969 Netherlands..... 6908528 June 4, 1969 Netherlands 6908529 [52] U.S. Cl 260/293.54, 424/267, 260/DIG. l3,

260/293.54, 260/293.83, 260/293.72, 260/297 R, 260/290 H, 260/293.76, 260/293.8, 260/471 A, 260/473 R, 260/476 R, 260/482 R, 260/293.86, 260/293.68, 260/483, 260/468 R, 260/297 Z [51] Int. Cl C07d 39/100 [58] Field of Search 260/293.54, DIG. l3, 260/293.84

[56] References Cited UNITED STATES PATENTS 3,345,373 10/1967 Gordon et al 260/D1G. 13

3,351,626 11/1967 Bartels-Keith et al. 260/D1G. 13

3,250,678 5/1966 Archer 260/DIG. l3

3,320,265 5/1967 1 Clarke 260/DIG. 13 3,322,778 5/1967 Kupchan et al 260/DIG. 13 3,514,463 5/1970 Robinson et al..... 260/DIG. 13 3,513,169 5/1970 Robinson et al..... 260/DIG. 13 3,553,223 l/l97l Leimgruber et al. 260/293.54

FOREIGN PATENTS OR APPLICATIONS 1,078,286 8/1967 Great Britain 260/293.84 1,079,489 8/1967 Great Britain 260/DlG. 13

OTHER PUBLICATIONS J. Org. Chem. 24 294 (1959) May et al. (Re-Print).

[451 Oct. 9, 1973 Primary Examiner-Henry R. Jiles Assistant Examiner-S. D. Winters Attorney-Lewis H. Eslinger, Alvin Sinderbrand and Curtis, Morris and Safford 5 7 ABSTRACT 6,7-benzomorphan derivatives having analgesic and morphine-antagonistic properties are of the formula in which the substituents R are either lower alkyl groups or groups which, together with the carbon atom to which they are bonded, form a cycloaliphatic 4 Claims, No Drawings 1 9,9-Dl-SUBSTITUTED -6,7-BEN ZOMORPHANS The invention relates to new 6,7-benzomorphan derivatives, methods for the preparation of these compounds and new intermediates which are useful in obtaining such derivatives.

The synthesis of 6,7-benzomorphans was described for the first time by E.L. May and LG. Murphy, J. Org. Chem. 20, 257 (1955). Since then, compounds of this type have drawn attention by reason of their interesting pharmacological properties. In particular, 6,7- benzomorphans not only show strong analgesic activity, but can also display activities which may be considered antagonistic to the action of morphine, depending on the nature of the substituent at the ring nitrogen atom. Such a combination of properties may lead to analgesic drugs practically devoid of the usual side effects of the classic strong analgesics, such as depression of respiration, development of tolerance and addiction.

Since the above publication of May et al. several series of 6,7-benzomorphans have been synthesized and identified, for example, as in U.S. Pat. Nos. 2,924,603, 3,033,867 and 3,138,603.

Moreover new drugs of this type have appeared, for instance, phenazocine and pentazocine, both of which have been introduced in therapeutics, and cyclazocine; Alternative routes of synthesis to arrive at 6,7- benzomorphans have been described, for example, in U.S. Pat. Nos. 3,073,837 and 3,093,650.

The chemistry and the pharmacology concerning 6,7-benzomorphans have been reviewed by N.B. Eddy and EL. May in: International Series of Monographs in Organic Chemistry, Vol. 8, Part II (B), Pergamon Press 1966).

The existing literature indicates that, in order to possess high activity, 6,7-benzomorphan compounds must have a quaternary carbon atom at position 5 in thering system, whereas, at position 9, the carbon atom should be preferably tertiary, at least, if the nomenclature "quaternary carbon atom is restricted to those connected exclusively to other carbon atoms not belonging to functional groups. Heretofore', no publications have appeared concerning 6,7-benzomorphan's having a quaternary carbon atom at position 9. The methods commonly used in the synthesis of benzomorphans are not feasible for the preparation of this type of compounds.

Now it has been found that 6,7-benzomorphans with the general formula ates in the preparation of compounds with such proper ties.

Of particular importance are the derivatives with the formula I'll R l Ra Formula L in which both constituents R have the above defined meaning, R, is a hydrogen atom or an alkyl, haloalkyl, alkenyl, alkinyl, aralkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenyl-alkyl or cycloalkylidenealkyl group preferably containing no more than nine carbon atoms, R is an alkyl, aryl, heteroaryl or aralkyl group and R is a hydrogen atom or-a hydroxy, alkoxy, alkoxyalkoxy or acyloxy group. Particularly preferred are those derivatives in which R, is a hydrogen atom or a methyl, allyl, 3methyl-2-butenyl, cyclopropylmethyl, cyclobutyL methyl or phenethyl group.

The new compounds according to the invention may be resolved into optical enantiomers, and pharmacological evaluation of the enantiomers has demonstrated that the desired activity resides largely in the levorotatory enantiomers.

The new compounds according to the invention may be administered as such or in the form of their therapeutically acceptable salts, in the usual manner.

As stated already, the compounds according to the invention cannot be prepared by processes commonly used in benzomorphan chemistry. Therefore, new routes for their synthesis have had to be devised.

in elaborating these new routes, it has been found possible to prepare the preferred compounds by means of cyclization of new substituted 2-benzyl-4 piperidinols of the general formula Formula llI inwhich the substituents R and R, have the above de fined meanings, R", is an alkyl or aralkyl group, and R';, stands for a hydrogen atom or a hydroxy or alkoxy group. If desired, the cyclization may be followed by the introduction of new substituents and/or by replace ment of substituents already present.

The mechanism of the cyclization probably proceeds via a carbonium ion having the structure of the formula fo mula .I\'

above mentioned 4-piperidinol would be the obvious starting material. The cyclization of 2-benzyl-4- piperidinols has been described for the synthesis of already known benzomorphan derivatives by H. Henecka et al. in British patent specification 1,079,489. However, in said publication, the 4-piperidinols used do not have more than one substituent at position 3.

Another example of the cyclization of corresponding 4-piperidinols, however, devoid of any substituent at positions 3 and 4, has been published by M. Takeda et al. in J. Org. Chem. 34, 4154 (1969) after the priority date of the present application. The Dutch patent application 69.00081, also published after such priority date, discloses among other things, the preparation of N-acylbenzomorphans from N-acyl-2-benzyl-4- piperidinols, however, without any example and without an indication how these piperidinols should be prepared. For the sake of completeness mention may be made of Teotino (J. Org. Chem. 27 (1962,11), 1906) in which the author synthesized 1-methyl-2-benzyl-4- piperidinol as a potential precursor of Z-methylbenzomorphan but did not describe the definitive cyclization.

The cyclization reaction described herein is preferably carried out at elevated temperatures and with the aid of a strong inorganic acid, preferably hydrobromic acid or phosphoric acid. During the reaction, alkoxy substituents at the benzene nucleus are converted into hydroxy groups.

Derivatives with R H are obtained from 2-methylbenzomorphans according to Formula II, having R CH, by the known technique of von Braun, whereby these Z-methyl derivatives are treated with cyanogen bromide and the formed 2-cyano-benzomorphans are saponified and subsequently decarboxylated. Another route to benzomorphans unsubstituted at the nitrogen atom consists in removal of the benzyl group from the 2-benzyl analogues by catalytic hydrogenolysis.

Hereupon, other substituents may be introduced on the nitrogen atom according to methods which are usually applied in benzomorphan chemistry, such as reaction with alkylhalides or acylhalides. 1n the latter case amides are formed which can be reduced to tertiary amines by means of lithium aluminum hydride.

If both substituents at position 9 are the same or form part of a cycloalkane ring, the new benzomorphans, in contrast with the known derivatives with one substituent at that position, possess two instead of three asymmetric carbon atoms (namely Cl and C Since the piperidine ring in th benzomorphan ring system can exist only in cis position relative to the remaining (tetralin-) part of the molecule, the new 6,7- benzomorphans can consequently arise only in one racemic form. To obtain optically active enantiomers of these new 6,7-benzomorphans, the resolution is carried out preferably with compounds having R, H, whereupon the optically active substances obtained may be substituted on the nitrogen atom according to the methods described above. The resolution can be achieved advantageously with the aid of and 3-bromocamphor-8 -sulphonic acid.

The previously mentioned intermediates according to Formula [[1, and also those wherein R stands for an alkinyl group, have not been described hitherto in the literature. As stated above, related compounds having only one alkyl substituent at position 3 of the piperidine ring have been prepared by H. Henecka et al for example, as described in British patent specification 1,078,286. However, they were prepared according to a method different from those described herein.

The new intermediates can be obtained by reduction 5 of the corresponding 2-benzyl-4-piperidones having the formula lil'i CH: /N\

METHOD 1:

B-amino esters of the formula NH: R

l R Formula VI in which R";, represents a hydrogen atom or an alkoxy group, are reacted with alkyl acrylates or with B-halopropionic esters, whereupon the products obtained may be substituted on the nitrogen atom. As a result, there are formed esters of 3,3-- -imino-dipropionic acid having the formula C 0 O Alkyl Formula VII Such alkyl 4-oxo-3-piperidine carboxylates are hydrolyzed and decarboxylated to give 4-piperidones having the formula The amino esters of Formula Vl, which are used as starting materials in this synthesis can be prepared from B-keto esters [Lapin et al., Gazz. Chim. ltal. 93, 451

(l963)] having the formula by conversion, with the aid of benzylamine, into benzylimino estershaving the formula R H ram-Q-cm-c-if-oo OAlkyl Formula XI These benzylimino esters can be saturated by catalytic hydrogenation to afford benzylamino esters having the formula ,F or nult XII The N-benzyl group may be removed from the compounds of formula XII, by means of catalytic hydrogenolysis, to afford the desired amino esters of formula VI.

The conversion of the B-keto esters of formula X into the B-benzylimino esters of formula X1 can be carried out in the usual way, that is, by reaction with benzylamine in the presence of a strongly acid catalyst (for instance p-toluenesulphonic acid or boron trifluoride diethyl etherate) in a solvent, such as toluene, which enables the removal of the formed water by meansof azeotropic distillation. However, more profitably, the method of H. Weingarten et al., J. Org. Chem. 32, 3246 (1967), can be used, in which titanium tetrachloride acts as the condensing agent in an inert solvent, such as toluene, and at room temperature.

The reduction of the B-benzylimino esters to the B-benzylamino esters of formula XII occurs by catalytic hydrogenation with platinum oxide as the catalyst. The removal of the benzyl group, givingrise to the above B-amino esters of formula V] is effected by catalytic hydrogenolysis, with palladium as the preferred catalyst, for instance, palladium adsorbed at active charcoal. Said hydrogenation and hydrogenolysis are preferably carried out in an acid medium. Acetic acid, whether or not diluted with alcohol, appears to be a suitable solvent. These reductions can be carried out at atmospheric pressure and at room temperature.

The conversion of the B-amino esters of formula VI into the 3,3'-iminodipropionic esters of formula Vll results from the reaction with B-halopropionic esters, or, preferably, from the reaction with alkyl acrylates at an elevated temperature in the presence of acetic acid as a catalyst. The resulting imino esters can be provided with the above-mentioned substituents R", on the nitrogen atom. The introduction of a methyl group is effected by the well-known method of Clarke and Eschweiler, according towhich the imino esters are heated with a mixture of formic acid and aqueous formaldehyde.

The 3,3-iminodipropionicesters can be cyclizised under the influence of a basic condensation agent, such as sodium methoxide or sodium hydride, by boiling the reactants suspended or dissolved in an inert solvent, such as benzene, toluene or dimethyl formamide. The alcohol generated during the reaction, is removed by simultaneous distillation of the mixture. The products of this Dieckmann cyclization are 2-benzyl- 4-oxo-5- piperidinecarboxylic esters of formula VIII.

Hydrolysis and decarboxylation of the keto esters of formula Vlll to 4-piperidones of formula IX are effected by heating a solution of these compounds in an aqueous, strong inorganic acid whereby the tendency of formation of neutral material as a result of decomposition may be limited by a careful choice of the reaction conditions, which should not be too vigorous. ln 6 N hydrochloric acid, the reaction is completed within 30 to 50 minutes and, in 2 N hydrochloric acid, the reac tion. is completed within 5 hours, whereas, 1 N acid requires a reaction time of 12 hours. The last procedure is the preferred one.

METHOD 2 In this method, propionic esters, provided with a secondary amino function at the B-position, are acylated with the acid chloride of a mono ester of either a dialkyl malonic acid or a l,l-cycloalkanedicarboxylic acid to form amido dicarboxylic esters having the formula The products thus obtained are subjected to hydrolysis and then to decarboxylation so as to be converted into 2,4-piperidinediones having the-formula Formula XV In the diones of formula XV, the 4-oxo group is masked by conversion into a ketal group, which leads to compounds having the formula Fermula X V I in which X represents the protected oxo group. The 2- piperidones according to formula XVI are subsequently reacted with a benzyl lithium' to give 2- benzylidene piperidines having the formula I K b Formula XVII in which R":, represents a hydrogen atom or an alkoxy group, whereupon the benzylidene group is saturated to a benzyl group and the 4-oxo group is regenerated to give the desired 2-benzyl-4-piperidones having the formula Formula XVIII The 3,3-dialkyl-2,4-piperidinediones according to formula XV belong to a type which has been described by Schnider et al., for example, in Festschrift Emil Barell 1936, 195; German Patent specification 634,284 and Swiss patent specification 256,347. In these publications, the authors arrived at said compounds by catalytic reduction of the corresponding 2,4(1H,3H)- pyridinediones, which were obtained by a four-step synthesis, starting from 2,2-dialkyl acetoacetic esters.

The route of synthesis of compounds according to formula XV described hereinabove is a new one and seems to be more attractive than the less direct route used by Schnider. The new method consists in a cyclization according to Dieckmann applied to amido dicarboxylic esters according to formula XIII, followed by decarboxylation after hydrolysis of the formed 4,6- dioxo-piperidine-3-carboxylic esters of formula XIV. It may be remarked that the present procedure is reminiscent of the method applied by some authors to the syn:

thesis of certain l-aralkyl-2,4-piperidine diones which were devoid of further substituents at the piperidine ring or held a methyl or ethyl substituent at position 5, for example, Y. Ban, Pharm. Bull. (Japan) 3, 53 (1955); M. Barash, J.M. Osbond and J.C. Wickens, J. Chem. Soc. 1959, 3530', and AR. Battersby and J.C. Turner, J. Chem. Soc. 1960, 717.

The Dieckmann cyclization is carried out in the usual manner, namely by heating a solution of the amido dicarboxylic esters in an inert solvent, such as benzene, toluene or dimethyl formamide, in the presence of a basic condensing agent, such as, sodium methoxide, sodium hydride or sodium amide. The alcohol formed is removed continuously during the reaction by distillation.

The saponification and decarboxylation of the cyclization products occur in an aqueous acid medium, for example, 6 N hydrochloric acid, at boiling temperature whereby the reaction is completed within 30 to 50 minutes. Longer reaction times are required if the acid concentration is lower. Too vigorous reaction conditions should be avoided as otherwise the amide function also may be attacked.

The-necessary starting materials for the Dieckmann cyclization, such as, the amidodicarboxylic esters of formula XIII are obtained in a simple manner by reaction of 2,2-dialkylmalonic acid mono-ester chlorides or l-chloro-formyll -cycloalkanecarboxylic acid esters with B-alkylamino or B-aralkylamino propionic esters in a basic medium, for instance in an ethereal solution to which pyridine or triethylamine is added, or in pyridine proper as the solvent.

In order to enable the introduction of a benzyl group at position 2 of compounds according to the formula XV, the keto function at position 4 has to be masked beforehand. For that purpose, this function is converted into a ketal group, preferably an ethylene ketal grouping. These ketals of formula XVI, wherein X is O-CH -CH O, are brought into reaction with benzyl lithium or p-alkoxybenzyl lithium. These lithium compounds are easily accessible according to the method of Gilman by reaction of lithium with benzyl ethyl ether [(I-I. Gilman et al., J. Org. Chem. 23, 2044 (1958) and 26, 3723 (1961)], or according to the invention, with p-methoxybenzyl ethyl ether. A mixture of tetrahydrofuran and ethyl ether is the preferred solvent in this reaction. As a result of the conversion of the lithium compounds with the N-substituted lactam function in Formula XVI, 2-benzylidene-piperidines having the formula XVII (wherein X -OCH- ,Cl-I O) are obtained, which are saturated to 2- benzyl-piperidines by means of catalytic hydrogenation.

Regeneration of the 4-oxo group is brought about by hydrolysis of the ketal function. As stated above this hydrolysis should be carried out in an acidic aqueous medium, such as hydrochloric acid, under conditions which are sufficiently controlled in consideration of the limited stability of the desired 2-benzyl-4-piperidones of formula XVIII.

As to the conversion of the 4-piperidones of formulas V, IX or XVIII into the corresponding 4-piperidinols, this can be effected by catalytic hydrogenation, as well as by other methods which are commonly used in the reduction of a carbonyl to a carbinol group.

Complex metal hydrides, such as, sodium borohydride or notably lithium aluminum hydride, are suitable for obtaining 4-piperidinols of formula III in which R =H. In order to prepare 4-piperidinols in which R =alkyl, aryl, heteroaryl or aralkyl, the 4-piperidones are brought into reaction with organo metal compounds, preferably lithium compounds. The reaction with methyl lithium, with phenyl lithium and with 2- pyridyl lithium leads smoothly to the desired 4- piperidinols with R =CH C H and 2--C -,H,N, respectively. However, with ethyl lithium, and more pronounced with propyl lithium, the reaction takes a less complete course and it is advisable to repeat the reaction in order to arrive at higher yields.

Moreover the 4-ethyl-4-piperidinols may be prepared in excellent yields via 4-ethinyl-4-piperidinols which are products of the reaction of the 4-piperidones with a mono alkalimetal salt of acetylene under suitable conditions. These conditions are, for instance, reaction with ethinyl lithium in liquid ammonia, reaction with ethinyl potassium in tertiary butanol at a temperature below zero, or reaction with the complex of ethinyl lithium and ethylenediamine in dimethylformamide at temperatures between zero and room temperature. The 4-ethinyl substituent can be converted into a 4-ethyl group by means of catalytic hydrogenation. In this way 4 ethyl-4-piperidinols may be obtained in a better yield than by the one step reaction with ethyl lithium.

When the 4-piperidinols are prepared from 4 piperidinones, a second asymmetric carbon atom emerges in the piperidine ring and, therefore, the 4- piperidinols may arise in two different racemic forms, both of which equally suit the conversion into the same 6,7-benzomorphan derivatives. As a consequence separation of the racemates is not necessary.

The 2-benzyl-4-piperidinols with R:, hydroxy and the corresponding 4-piperidinones are compounds according to this invention as well as the derivatives in which R' has the other defined meanings. Nevertheless, insofar as it is an object of the invention to provide starting materials for the new benzomorphan deriva-' tives, it is irrelevant to prepare the compounds with R;, hydroxy separately, as 2-benzyl-4-piperidinols with R; hydroxy, as well as those with R';, alkoxy, will lead to the same 6,7-benzomorphans by reason of the fact that, under the given reaction conditions, alkoxy substituents usually will be converted into hydroxy groups.

It will be clear that, if an acid chloride of a mono ester of a mono alkyl malonic acid is selected as the starting material, the present synthesis (method 2) will lead to 3-mono alkyl substituted 2-benzyl-4- piperidinols, a type which has been described by H. Henecka et al. in the above-mentioned British patent specification 1,078,286 and which can serve as'an intermediate in the preparation of previously known 6,7-

benzomorphans.

The invention will now be further illustrated by the following specific, non-limiting examples.

EXAMPLE 1 Methyl 2,2-dimethyl-4-(p-methoxypehnyl)- acetoacetate To a gently refluxing suspension of 227 g of granulated zinc, activated by the addition of l g of iodine, in 500 ml of dry tetrahydrofurane there is dropped with mechanical stirring and under exclusion of moisture, a solution of 700 g of methyl 2-bromoisobutyrate and 540 g of methyl p-methoxy-phenylacetate in 500 ml of tetrahydrofurane. As soon as the reaction has started, apparent from the formation of a turbidity and stronger Re the d t o is ,wntinueda sh irat s to maintain gentle reflux with minimal application of external heating. After all of the solution has been added, stirring and refluxing is continued for 5 hours. Then the reaction mixture is cooled with ice and 1500 ml of 4 N sulphuric acid is added dropwise with vigorous stirring. The organic layer is separated, after the eventual removal of some solid material by filtration, and the aqueous solution extracted with ether. The combined organic solutions are washed with an aqueous solution of sodium bicarbonate. Evaporation of the solvent leaves the crude ester which is purified by distillation in vacuo. Yield 60 65%, boiling point 145C (1 mm), i 1.5140.

EXAMPLE 2 Methyl 2,2-dimethyl-4-phenyl-acetoacetate 1n the same manner as described in example 1, however, starting from methyl phenylacetate, the abovementioned compound is prepared. Yield 71 percent, boiling point 112C (1 mm), n 1.5043.

EXAMPLE 3 Methyl 3-benzylamino-2,2-dimethyl-4-(p-methoxyphenyl)-butyrate Titanium tetrachloride (l 14 g) is dropped over a period of 2 hours to a mixture of 250 g of methyl 2,2-

' dimethyl-4-(p-methoxyphenyl)-acetoacetate, 384 g of benzylamine and 1,000 ml of dry toluene. The mixture -is kept in an atmosphere of nitrogen, stirred vigorously 'quently, the crude Schiff base (920 g), dissolved in 1.25 l of acetic acid is hydrogenated with the aid of 5 g of platinum oxide as a catalyst and at atmospheric pressure. Hydrogen uptake is rapid at first but after absorption of 55 1 it slackens down considerably. At that point the hydrogenation is interrupted whereupon the catalyst is removed by filtration and the solution concentrated by evaporation of the solvent in vacuo. The residue is taken up in water and the resulting aqueous solution made alkaline with the aid of 4 N sodium hydroxide. The basic material which separates is taken up in ether. Removal of the solvent by evaporation leaves an oily residue which is dissolved in 700 ml of ethanol. After cooling overnight in the refrigerator a crop of 440 g of coarse crystals has deposited from the solution. Recrystallisation from ethanol gives the pure 1 product, melting at 58 60C.

EXAMPLE 4 i Methyl 3-benzylamino-2,2-dimethyl-4-phenyl-butyrate A mixture of 440 g of methyl 2,2-dimethyl-4-phenylacetoacetate, 214 g of ben'zylamine, 500 ml of toluene and 2 ml of boron trifluoride etherate is refluxed under continuous removal of the water formed by azeotropic distillation. After 16 hours, when only one half of the water expected has been separated, g of benzyl-. amine and 2 ml of a solution of hydrogen bromide in acetic acid (45 percent) are added and refluxing is continued for 25 hours after which the formation of water om Th z mrs i shaken withst qusmts..-

solution of sodium bicarbonate, dried over magnesium sulphate and distilled at reduced pressure. The fraction with boiling range 147 170C (0.2 mm) consists largely of ketimine (500 g), suited to hydrogenation without further purification. Fractional distillation affords pure ketimine with a boiling range of 149 152C (0.25 mm), n 1.5532. Crude ketimine 500 g), dissolved in 500 ml of acetic acid, issubmittedto catalytic hydrogenation at atmospheric pressure and room temperature, and with platinum dioxide (2 g) as a catalyst. Hydrogen uptake stops with 24 1. After removal of the catalyst by filtration, the solvent is evaporated completely in vacuo. The oily residue is dissolved in ca. 250 ml of ethanol. From this solution the above compound separates in coarse crystals. Yield 220 g, melting at 92 94C.

EXAMPLE 5 EXAMPLE 6 Methyl 3-amino-2,Z-dimethyl-4-phenyl-butyrate In a similar way as described in example 5 hydrogenolytic debenzylation of methyl 3-benzylamino- 2,2-dimethyl-4-phenyl-butyrate affords the abovem'entioned compound as an oil which solidifies on standing. Melting point 37 39'C. Yield 34 percent,

based on the amount of methyl 2,2-dimethyl-4-phenylacetoacetate used.

EXAMPLE 7 Dimethyl 3-(p-methoxybenzyl)-2,2,N-trimethyl-3,3'- iminodipropionate w A mixture of 351 g of methyl 3-amino-2,2-dimethyl- '4-(p-methoxyphenyl)-butyrate, 205 g of methyl acrylate and 3 ml of acetic acid is heated in an autoclave during 18 hours at 130C. The contents is removed from the autoclave with the aid of ether whereupon the volatile material is evaporated at diminished pressure. To the resulting crude reaction product are added dropwise successively 280 ml of formic acid (95%) and 280 ml of aqueous formaldehyde (35 percent). During this operation, which takes 1.5 hours, the mixture is stirred and cooled with water.

Subsequently, it is warmed at 40C for 1 hour, kept at room temperature during 16 hours and finally warmed one additional hour at 60C. After removal of low boiling material by evaporation in vacuo, the resulting oil is treated with chloroform and a concentrated aqueous solution of potassium carbonate. The organicv solution is dried over magnesium sulphate and evaporated, leaving an oily residue. Neither this product nor its unmethylated predecessor can be purified by distillation because of extensive decomposition at elevated temperatures. p The first step of the synthesis described in this example may of also carried out at a lower temperature without the use of an autoclave. In this case, a mixture of 450 g of methyl 3-amino-2,2-dimethyl-4-(p-methoxyphenyl)-butyrate and 180 ml of methyl acrylate is 5 stirred at 50C when 45 ml of acetic acid is added rather rapidly. The temperature of the mixture is raised to 90C by application of heat and then rises spontaneously to 100C. After one hour the reaction has ended; the excess ov methyl acrylate and acetic acid is removed by evaporation in vacuo at 50C.

EXAMPLE 8 Methyl 2-(p-methoxybenzyl)-4-oxo-l,3,3-trimethyl-5- piperidine-carboxylate hydrochloride The crude methylimino dipropionic ester prepared according to the method described in example 7- is dissolved in 3 of dry toluene. Sodium methoxide (157 g) is added and the mixture is stirred and heated in an oil bath at 100- 1 10C. The methanol which is generated during the reaction is removed by azeotropic distillation. Its formation comes to an end after two and a half to three hours when merely toluene is distilled. The mixture is cooled whereafter water is added. The toluene layer is washed with water and, after being dried with magnesium sulphate, evaporated in vacuo. The residue, consisting of crude keto ester is treated with an alcoholic solution of hydrogen chloride. The hydrochloride separates as a crystalline precipitate. The yield is 268 g (54 percent, based on the quantity of starting amino ester described in example 5). Melting point 163 164C (decomp.).

' EXAMPLE 9 Methyl 2-(p-methoxybenzyl)-4-oxo-1,3,5-trimethyl-5- piperidine-carboxy-late hydrochloride To a solution of 19.0 g of crude methyliminodipropionic acid ester, prepared according to example 7, in 150 ml of dry dimethylformamide,,there is added 4.8 g of sodium hydride percent dispersion in oil), the mixture being stirred and gradually heated until, at about C, a vigorous evolution of hydrogen takes place. The reaction is completed by heating the mixture at 1 10 C during three hours. After cooling a solution of 30 g of ammonium chloride in 300 ml of 45 water is added, whereupon the solvents are removed by evaporation in vacuo. The residue is shaken with l N hydrochloric acid and benzene. The acidic aqueous layer is made alkaline with an excess of aqueous ammonia and subsequently extracted with chloroform. The 0 organic solution is processed as usually and the product is secured as the hydrochloride. The compound is identical with the one obtained according to example 8. After recrystallization the yield is 49 percent.

55 EXAMPLE 10 Ethyl 3,3-dimethyl-2-(p-methoxybenzyl)-4-oxo-5- piperidine-carboxylate hydrochloride In a manner similar to the method described in example 8, however, starting from the addition product of the reaction of ethyl acrylate with methyl 3-amino-2,2- dimethyl-4-(p-methoxyphenyl)-butyrate (prepared according to the method depicted in example 7), the 1 above-mentioned compound is obtained. The yield of the substance amounts to 33 percent. The melting point, after recrystallization from ethanol, is 177 180C.

EXAMPLE 11 Ethyl 2-benzyl-4-oxo-1,3 ,3-trimethyl-- piperidinecarboxylate hydrochloride A mixture of 240 g of methyl 3-amino-2,2-dimethy1- 4-phenyl-butyrate, 171 g of ethyl acrylate and 1.5 ml of acetic acid is heated at 130C for 18 hours. The crude addition product (365 g) is methylated by means of the Clarke-Eschweiler method, as described in example 7. As a result 325 g of an iminodipropionic mixed ester is obtained as an oil. This compound (325 g) is submitted to a Dieckmann cyclization by reaction in toluene with 90 g of sodium methoxide under conditions as described in example 8.

In working up, the reaction mixture is neutralized by the addition, with cooling, of acetic acid and afterwards washed with water and processed as usually. The yield of the hydrochloride is 52 percent. Recrystallized from ethanol/acetone the compound melts at 180 182C, with decomposition.

EXAMPLE l2 2-(p-Methoxybenzyl)-l ,3,3-trimethyl-4-piperidone hydrochloride A solution of the hydrochloride (80 g) of methyl 2- (p-methoxybenzyl)-4-oxo-l ,3 ,3-trimethyl-5- piperidinecarboxylate in 450 ml of 1 N hydrochloric acid is refluxed for 12 hours. After cooling, some resinous material is removed by extraction with ether. Alkalinization of the aqueous solution with the aid of ammonia causes the separation of the piperidone which is extracted with ether. Concentration in vacuo of the extract gives a residue which is dissolved in ethanolic hydrogen chloride. Evaporation of the ethanol leaves a syrupy residue which is dissolved in acetone, whereafter the crystalline hydrochloride separates. Yield 87 percent. Melting point 168 170C, with decomposition. I

EXAMPLE 13 2-Benzyl-1 ,3 ,3-trimethyl-4-piperidone hydrochloride A solution of 217 g of the hydrochloride of ethyl 2- benzyl-4-oxo-l,3,3-trimethyl-3-piperidine carboxylate in 6 N hydrochloric acid is refluxed for 40 minutes. The piperidone is gathered as the hydrochloride in the same way as described in example 12. Yield 75 percent; melting point 177 179C, with decomposition.

EXAMPLE 14 EXAMPLE l5 3,3-Dimethyl-2-(p-methoxybenzyl)-4-piperidone drochloride Starting from 19.1 g of crude 3-(p-methoxybenzyl)- 2,2-dimethyl-3,3-imino-dipropionic acid dimethyl ester (obtained from the addition-reaction of methyl acrylate with 3-amino-2,2-dimethyl-4-(p-methoxy' phenyl)-butyric acid methyl ester), dissolved in 150 ml of dry dimethylformamide and in the presence of 7.2 g

of sodiumhydride (50 percent dispersion in oil), a Dieckmann condensation is carried out as described in example 9. The crude condensation-product is hydrolyzed and decarboxylated as described in example 12, giving the desired piperidine in an overall yield of 44 percent.

EXAMPLE 16 l-Benzyl-3 ,3-dimethyl-2-( p-methoxybenzyl )-4- piperidone hydrochloride A mixture of 24.5 g of crude dimethyl 2,2-dimethyl- 3-(p-methoxybenzyl) 3,3'-iminodipropionate, 27 g of benzyl chloride, 23 g of potassium iodide, 40 g of potassium carbonate and 300 ml of methyl ethyl ketone is refluxed and stirred during 35 hours. The mixture is cooled and evaporated in vacuo whereupon the residue is treated with chloroform. Inorganic material is removed by filtration and the filtate is concentrated in vacuo leaving a residue which is shaken with 300 ml of 4 N hydrochloric acid and 100 ml of petroleum ether in order to remove neutral products. After basification with aqueous ammonia, the N-benzyl-2,2-dimethyl-3- (p-methoxybenzyl)-3,3'-iminodipropionic acid dimethyl-ester is extracted from the mixture by shaking with chloroform. lt is obtained in nearly quantitative yield, and, without purification submitted to a Dieckmann cyclization using 5.2 g of sodium hydride percent dispersion in oil) and 200 ml of dimethylformamide. Further processing is carried out according to the direc tions already described in preceding examples, giving the above-mentioned product which is recrystallized from ethanol/ether. Yield 35 percent. Melting point 161 162C, with decomposition.

EXAMPLE 17 Diethyl 3-oxo-2,2,N-trimethyl-3,3-iminodipropionate To a solution of 61 g of N-methyl-B-alanine ethyl I ester in 600 ml of dry pyridine there is added dropwise 82 gv of ethyl 2-chloroformyl-2-methylpropionate. During the addition, which takes 30 minutes, the mixture is mechanically stirred and cooled with ice. Stirring is continued at 10C for 30 minutes and then at 30 40C for 1 hour. Next the pyridine is evaporated in vacuo, leaving a residue to which a small quantity of water is added, whereafter the mixture is extracted with ether. The extract is dried over magnesium sulphate and evaporated leaving the above-mentioned product as a liquid which is purified by distillation at reduced pressure. Yield 97 g percent). Boiling point 134 136C (1 mm). n 1.4565.

EXAMPLE l8 Dimethyl 2,2-diethyl-N-methyl-3-oxo-3 ,3 iminodipropionate To a solution of 19.2 g of methyl 2-chloroformyl-2- ethyl-butyrate and 20 g of triethylamine in 100 ml of dry ether, which is mechanically stirred and cooled at -l0C, there is added dropwise 12.8 g of N-methyl-B- alanine methyl ester dissolved in 50 ml of dry ether. After the addition, which takes 30 minutes, the mixture is stirred during 18 hours at room temperature. After filtration of the separated triethylamine hydrochloride, the solvent is evaporated leaving the desired product as an oil, boiling at 118C (0.2 mm). Yield 93%.-n,, 1.4646.

EXAMPLE I) Diethyl N-methyl-3-oxo-2,2-tctramethylene-3 ,3

iminodipropionate In a similar manner as described in example 18, however, starting from 83.9 g of l-chloroformyl-lcyclopentane-carboxylic acid ethyl ester, 59 g of N-methyl-B-alanine ethylester and 83 g of triethylamine, the above-mentioned compound is obtained. Yield 81 percent. Boiling point 129 133C (0.3 mm).

EXAMPLE 20 Diethyl N-methyl-3-oxo-2,2-pentamethylene-3 ,3 iminodipropionate In a similar manner as described in example 18, however, starting from 39.6 g of l-chloroformyl-lcyclohexanecarboxylic acid ethyl ester, 24 g of N-methyl-B-alanine ethyl ester and 36 g of triethylene, the above-mentioned compound is obtained. Yield 84 percent. Boiling point 166 169C (1 1.5 mm).

EXAMPLE 21 Diethyl N-benzyl-2,2-dimethyl-3-oxo-3 ,3 iminodipropionate In a similar manner as described in example 18, however, applying N-benzyl-B-alanine ethyl ester, the above compound is obtained. Yield 76 percent. Boiling point 184 190C (0.3 0.4 mm).

EXAMPLE 22 1 ,3 ,3-Trimethyl-2,4-piperidinedione A mixture of 97 g of diethyl 3-oxo-2,2,N-trimethyl- 3,3-iminodipropionate, 450 ml of toluene and 42 g of sodium methoxide is stirred mechanically and boiled under continuous removal of the ethanol formed by means of azeotropic distillation. After 3 hours, when the boiling point of toluene is reached, the mixture is cooled and made weakly acidic with the aid of 4 N hydrochloric acid.

The toluene layer is washed with water and the aqueous solutions are extracted three times with ether. After drying over magnesium sulphate the combined organic solutions are stripped of the solvents by evaporation in vacuo. To the crude condensation product which is left as an oil, 300 ml of hot 6 N hydrochloric acid is added and the resulting solution is refluxed for 40 minutes. After rapid cooling, the mixture is made alkaline with the aid of aqueous ammonia and then extracted with chloroform. The extract is dried over magnesium sulphate and evaporated in vacuo.

The product is purified by distillation. Yield 64 percent. Boiling point 93 98C (1 mm). It solidifies, and melts at 39 42C after recrystallization from petroleum ether.

EXAMPLE 23 3 ,3-Diethyll -methyl-2,4-piperidinedione In a manner similar to the method described in example 22, however, starting from dimethyl 2,2-diethyl-N- methyl-3-oxo-3,3'-iminodipropionate, the abovementioned compound is obtained. Yield 75 percent. Boiling point 102- 104C (0.2 0.3 mm). n 1.4850.

EXAMPLE 24 1-Benzyl-3,3-dimethyl-2,4-piperidinedione In a manner similar to the method described in example 22, however, starting from diethyl N-benzyl-2,2- dimethyl-3-oxo-3,3'-iminodipropionate, the abovementioned compound is obtained. Yield 44%. The product melts at 68 70C (crystallized from petroleum ether).

EXAMPLE 2s 7-Methyl-7-azaspiro [4.5] decane-6,10-dione A boiling mixture of 700 ml of toluene, 94.4 g of diethyl N-methyl-3-oxo-2 ,2-tetramethylene-3 ,3 iminodipropionate and 40 g of sodium methoxide is stirred mechanically while the ethanol generated during the reaction is removed by azeotropic distillation.'

After 3 hours the boiling point of toluene has been reached, 300 ml of distillate being collected. After the addition of 60 g of ammonium chloride, stirring is continued for another 30 minutes when, after cooling, water is added. The organic solution is separated, dried and evaporated in vacuo. The residue (77 g) is hydrolyzed and decarboxylated by means of heating at C with 300 ml of l N hydrochloric acid during 18 hours. Processing as described in example 22 gives the abovementioned product. Yield 48 percent. Boiling point 138- 145C (1.5 2 mm).

EXAMPLE 26 2-Methyl-2-azaspiro [5.5] undecane-l,5-dione In a manner similar to the method described in example 25, diethyl N-methyl-3-oxo-2,Z-pentamethylene- 3,3'-iminodipropionate (43.2 g) dissolved in 250 m1 of toluene, is submitted to the Dieckmann cyclization, using 17 g of sodium methoxide.

The condesation product (34 g) is saponified and decarboxylated as described in the preceding example. The desired product is obtained in a 45 percent yield. Boiling point C (0.7 mm).

EXAMPLE 27 6,6,8-Trimethyl-l ,4-dioxa-8-azaspiro 7-one This ketal is prepared by refluxing a solution of 6.5 g of 1,3,3-trimethyl-2,4-piperidinedione, 5 g of ethylene glycol and 30 mg of p-toluenesulphonic acid in 45 ml of benzene during 19 hours. The water formed is separated with the aid of a Dean-Stark trap. After shaking the solution with saturated aqueous sodium bicarbonate, it is dried over magnesium sulphate, whereafter the solvent is evaporated in vacuo. The residue is recrystalled from petroleum ether. Yield 5 g. Melting [4.5] decanpoint 69 72C. From the mother liquor an additional 7 EXAMPLE 29 8-Benzyl-6,6-dimethyl-1,4-dioxa-8-azaspiro [4.5] decan-7-one In a manner similar to the method described in example 27, however, applying 1-benzyl-3,3-dimethyl-2,4- piperidinedione, the above-mentioned ketal is obtained in a 86 percent yield. After recrystallization from petroleum ether it melts at 77 79C.

EXAMPLE 30 l2-Methy1-l,4-dioxa-l2-azadispiro [4.0.4.4] tetradecan-1 l-one A solution of 26 g of 7-methy1-7-azaspiro [4.5] decane-6,l-dione in 150 ml of ethylene glycol, containing 100 mg of p-toluenesulphonic acid, is distilled at atmospheric pressure until 1 ml of distillate has been col lected. The distillation residue is then shaken with ether and dilute aqueous ammonia. The aqueous layer is extracted with chloroform and the combined organic solutions are dried and evaporated in vacuo. The residue is recrystallized from ether. Melting point 84 85C. Yield 56 percent.

EXAMPLE 31 l3-Methyl-l,4-dioxa-13-azadispiro [4.0.5 .4] pentadecan-12-one In a manner similar to the method described in example 30, the above ketal is prepared from 12.9 g of 8-methyl-8-azaspiro [5.5] undecane-1,5- dione. Yield 50 percent. Melting point 91 92C (recrystallized from ether).

EXAMPLE 32 2-(p-Methoxybenzyl)-l ,3,3-trimethyl-4-piperidone hydrochloride A solution of p-methoxybenzyl lithium is prepared according to the directions given by Gilman, et al. for the preparation of benzyl lithium. To this purpose 1.4 g of lithium wire, cut into small pieces, is suspended in 20 ml of dry perioxide free tetrahydrofurane. Under cooling (lOC), mechanical stirring and flushing with nitrogen, there is added 0.5 ml of a solution of pmethoxybenzyl ethyl ether in absolute ether (5 g dissolved in ml of ether). After 1 1.5 hour the reaction starts, which is recognisable by the development of a yellow-orange colour. Then the remainder of the ethereal solution is added dropwise with cooling (lOC) over a period of 2 hours.

Cooling and stirring are continued for an additional 18 hours whereafter the p-methoxybenzyl lithium contents of the brown-red solution is determined by titration as described by Gilman. To a mechanically'stirred and nitrogen flushed ethereal solution (15 ml) of 1.5 g of 6,6,8-trimethy1-1,4-dioxa-8-azaspiro [4.5] decan- 7-one which is cooled in ice, there is added dropwise 40 ml of a 0.2 molar solution of p-methoxybenzyl lithium, as prepared above. The addition lasts 1 hour whereafter, under continuous stirring, the mixture is allowed to come to room temperature gradually (16 hours). Water is added (cooling with ice) and the organic layer is washed three times with water. After drying and evaporation in vacuo, a yellow oil (3.5 g) is obtained. The infrared spectrum (in carbon tetrachloride) demonstrates the absence of starting material (absence of the amide carbonyl band at 608p.) and the presence of the reaction product by a strong band at 6.2;1. (conjugated C C). The oil is dissolved in 75 ml of ethanol and submitted to catalytic hydrogenation, with platinum oxide as the catalyst, at room temperature and normal pressure. Hydrogen absorption stops after an uptake of 130 ml.

After filtration the solution is concentrated in vacuo. The colourless oil which remains, is dissolved in 30 ml of 2 N hydrochloric acid and the solution is heated on the steam bath for 20 minutes to bring about the hydrolysis of the ketal function. After cooling, the mixture is made alkaline and extracted three times with ether.

The extract is processed as usual. The product is secured as the hydrochloride which is recrystallized from ethanol/acetone. Yield 31 percent. Melting point 173 C, with decomposition. As shown by the infrared spectra this product is identical with the one obtained according to example 12.

EXAMPLE 3 3 l-Benzyl-3,3-dimethy1-2-(p-methoxybenzyl)-4- piperidone hydrochloride In a manner similar to the method described in example 32, however, starting from 8-benzyl-6,6-dimethyl- 1,4-dioxo-8-azaspiro [4.5] decan7-one, the above compound is obtained in a yield of 14 percent. After recrystallization fromethanol/ether, the compound melts at 156 157C, with decomposition. As is shown by the infrared spectra this product is identical with the one obtained according to example 16.

EXAMPLE 34 2-Benzyll ,3,3-trimethyl-4-piperidone hydrochloride [n a manner similar to the method described in'example 32, however, applying a solution of benzyl lithium instead of p-methoxybenzyl lithium, the above product is obtained in a 88 percent yield. Melting point 176 179C, with decomposition.

EXAMPLE 35 2-Benzyl-3,3-diethyl-1-methyl-4-piperidone chloride In a manner similar to the method described in example 32, however, using benzyl lithium and 6,6-diethyl- 8-methy1-l,4-dioxa-8-azaspiro [4.5] decan-7-one as the reactants, the above-mentioned compound is obtained in a yield of 63 percent. After recrystallization from ethanol/ether the product melts at 163 164C, with decomposition.

EXAMPLE 36 EXAMPLE 37 6-Benzyl-7-methyl-7-azaspiro [4.5] decan-lO-one hydrochloride In a manner similar to the method described in examhydrople 32, however, starting from 12-methyl-1,4-dioxa-l2- azadispiro [4.0.4.4] tetradecan-ll-one, which in this case is reacted with benzyl lithium, the abovementioned compound is obtained. Yield 59 percent. After recrystallization from ethanol/acetone the substance melts at 156 157C.

EXAMPLE 38 l-Benzyl-2-methyl-2-azaspiro [5.5] undecan-S-one hydrobromide In a manner similar to the method described in example 32, however, starting from l3-methyl-l ,4-dioxal 3- azadispiro [4.0.5.4] pentadecan-lZ-one, which in this case is reacted with benzyl lithium, the abovementioned compound is obtained in the form of the free base. The product is isolated as the hydrobromide with a melting point of 155 l56C. Yield 41 percent.

EXAMPLE 39 2-( p-Methoxybenzyl)-l ,3,3 ,4-tetramethyl-4- piperidinol To a mechanically stirred and nitrogen flushed ethereal solution (200 ml) of methyl lithium (prepared in the usual manner from 43 g of methyl iodide and 4.8 g of lithium) there is added in small quantities 9 g of 2- (p-methoxybenzyl)- l ,3,3-trimethyl-4-piperidone hydrochloride. During the addition, which takes some 1.5 hour, the mixture is cooled with water. 1t is stirred at room temperature for 16 hours and finally refluxed for 1 hour. Then the lithium compounds are hydrolysed by careful addition of water (cooling with ice) and the basic material is extracted from the mixture with the aid of 4 N hydrochloric acid. Basification of the aqueous solution followed by extraction with ether and processing of the ethereal solution as usual, gives crystals which after recrystallization from petroleum ether melt at 55 65C. Yield 84 percent. Evidently a mixture of epimeric piperidinols has been formed.

EXAMPLE 40 2-(p-Methoxybenzyl)-3,3,4-trimethyl-4-piperidinol hydrochloride In a manner similar to the method described-in example 39, however, starting from 3,3-dimethyl-2-(pmethoxybenzyl)-4-piperidone hydrochloride, the above-mentioned compound is obtained. The substance is secured as the hydrochloride which crystallizes from a mixture of ethanol and ether. Melting point 211 213C with decomposition. Yield percent.

EXAMPLE 41 the 4-Ethyl-2-(p-methoxybenzyl)-l ,3,3-trimethyl-4- piperidinol hydrochloride The hydrochloride (18 g) of 2-(p-methoxybenzyl)- 1,3,3-trimethyl-4-piperidone is converted to the free base by shaking with ether and aqueous sodium hydroxide, followed by evaporation of the ethereal solution. The oily base is dissolved in 30 ml of absolute ether and subsequently reacted with ethyl lithium (3.6 g in 300 ml of benzene) under conditions as described in example 39. According to gaschromatographic examination, conversion to the piperidinol occurs to the extent of only 25 percent. After the addition of water the reaction mixture is worked up as described in example 39 and the crude mixture of piperidone and piperidinol so obtained is treated again with ethyl lithium (2.7 g in 250 ml of benzene). This procedure is repeated once more whereafter still percent of the piperidone appears to be present. Processing as usually furnishes 19 g of an oily base, which is converted to the hydrochloride with the aid of ethanolic hydrogen chloride. After the addition of acetone and ether, 9 g of the above crystalline product separates. Yield 45 percent. Melting point 232 234C with decomposition.

EXAMPLE 42 Z-(p-Methoxybenzyl)-4-propyl-1,3 ,3-trimethyl-4- piperidinol In a manner similar to the method described in example 41, however, applying n-propyl lithium instead of ethyl lithium, the above-mentioned compound is obtained in a 31 percent yield. After recrystallization from petroleum ether the substance melts at 102- C.

EXAMPLE 43 Z-Benzyl-l ,3,3,4-tetramethyl-4-piperidinol In a manner similar to the method described in example 39, however, starting from 2-benzyl-l,3,3-trimethyl-4-piperidone hydrochloride, the above-mentioned compound is obtained. Yield 69 percent. After recrystallization from light petrol, the substance melts at 103C.

EXAMPLE 44 EXAMPLE 45 2-Benzyl-4-ethyl-l ,3,3-trimethyl-4-piperidinol chloride A solution of 4.4 g of 2-benzyl-1,3,3-trimethyl-4- piperidone in 30 ml of absolute ether is added at room temperature and over a period of one hour to a Grignard reagent prepared from 1.1 g of magnesium, 5.5 g of ethyl bromide and 35 ml of absolute ether.

After the mixture has been stirred at room temperature during 2 days, it is cooled with ice, whereupon 25 ml of water is added. The ethereal solution is dried and acidified by means of ethanolic hydrogen chloride. The substance crystallizes as the hydrochloride, melting at 220 230C with decomposition. Yield 13 percent.

EXAMPLE 46 2-Benzyl-l ,3 ,3-trimethyl-4-piperidinol Hydrochloride A solution of 9 g of 2-benzyl-l,3,3-trimethyl-4- piperidone hydrochloride in 50 ml of methanol is submitted to catalytic hydrogenation at room temperature and atmospheric pressure, with 0.4 g platinum oxide as the catalyst. The product is crystallized from ethanol/ether. Yield 98 percent. Melting point, after recrystallization, 213 222C.

EXAMPLE 47 4-Ethinyl-2-(p-methoxybenzyD-1 ,3 ,3-trimethyl-4- piperidinol A stream of acetylene, after successively having been washed with water, cooled to 80C and dried with Ca- Cl is led into a mechanically stirred solution of 7 g of lithium in 750 ml of dry liquid ammonia which is cooled at about -50C. After about 5 hours the blue colour disappears. To the solution of acetylene lithium so obtained there is added dropwise 60 g of 2-(pmethoxybenzyl )-l ,3 ,3-trimethyl-4-piperidone dissolved in 250 ml of absolute ether. During the addition a slow stream of acetylene is maintained, but afterwards this is stopped and the reaction mixture is stirred for 16 hours, the ammonia being allowed to evaporate gradually. The resulting suspension is diluted by addition of 250 ml of absolute ether and stirred for another 2 hours at 30C. After cooling 54 g of ammonium chloride and water are added. The reaction product is sehydrohydrocured from the organic layer in the usual manner. It is recrystallized from a mixture of benzene and petroleum ether. Yield 88 percent. Melting point 103 110C.

EXAMPLE 4:;

4-Ethinyl-2-(p-methoxybenzyl l ,3,3-trimethyl-4- piperidinol Potassium (23.8 g) is dissolved in 500 ml of dry tertiary butanol whereupon 500 ml of absolute ether is ad-- ded. This solution is cooled with ice and saturated with dry acetylene (cf. example 47).

Then, in the course of 45 minutes, a solution of 59.5 g of 2-(p-methoxy-benzyl l ,3 ,3-trimethyl-4- piperidone in 250 ml of absolute ether is added dropwise, the mixture being cooled at -l to -l'C and stirred mechanically. Meanwhile the mixture is flushed with acetylene, which is continued for an additional 3 hours (at l0C).

Then the reaction mixture is allowed to come to room temperature in the course of 16 hours. After the addition of 53.5 g ammonium chloride, stirring-is continued for 30 minutes when 500 ml of ice-cold water is added. The organic solution is separated, dried and evaporated, leaving the desired product as a crystalline residue melting at 103 110C. Yield 98 percent.

EXAMPLE 49 4-Ethyl-2-( p-methoxybenzyl l ,3 ,3-trimethyl-4' piperidinol A solution of 56 g of 4-ethinyl-2-(p-methoxybenzyl)-' l,3,3-trimethyl4-piperidino1 in 350 ml of methanol is subjected to hydrogenation at atmospheric pressure and room temperature, the catalyst being 5 percent palladium on charcoal (5 g).

Absorption of 8.8 l of hydrogen takes place within 2 hours. Removal of the catalyst by filtration and evaporation of the ethanol in vacuo leaves 55 g of an oil, which solidifies completely. Yield 98 percent. Melting point 90 95C.

EXAMPLE 50 2-( p-Methoxybenzyl )-4-phenyll ,3 ,3-trimethy1-4- piperidinol In a manner similar to the method described in example 41, however, applying phenyl lithium instead of ethyl lithium, the above-mentioned compound is prepared. Yield 88 percent. Melting point 122 124C (after recrystallization from petroleum ether).

EXAMPLE 51 l Benzyl-2-(p-methoxybenzyl )-3 ,3 ,4-trimethyl-4- piperidinol hydrochloride 1n a manner similar to the method described in example 39, however, starting from l-benzyl-Z-(pmethoxybenzyl)-3,3-dimethyl-4-piperidone hydrochloride, the above compound is obtained. Yield 43 percent. Melting point, after recrystallization from ethanol/ether, 213 214C (decomp.).

EXAMPLE 52 2-Benzyl-3 ,3-diethyll -methyl-4-piperidinol To a solution of 6.4 g of 2-benzyl-3,3-diethyl-l-methyl-4-piperidone in 100 ml of ether, there is added within a few minutes, 0.9 g of lithium aluminum hydride. The mixture is stirred at room temperature during four hours. After the addition of 5 g of ammonium chloride stirring is continued for half an hour. Then the mixture is washed with ml of water and the ethereal solution is evaporated in vacuo. The residue is submitted to chromatography on aluminum oxide, a mixture of benzene-ethanol (98 2) being the eluent. The product, which shows no tendency to crystallization, is a mixture of two stereo-isomers. They can be separated easily by way of the picrates. Fractional crystallization of 6.5 g ofa mixture of picrates gives 2.7 g ofa picrate, melting at 206 208C, which is sparingly soluble in ethanol, and 2.7 g of an easily soluble picrate which melts at 162 164C. From the picrates the isomeric bases can be obtained as oils. 1f submitted to the cyclization procedure described in example 58, both isomers give rise to the same product.

EXAMPLE 53 2-(p-Methoxybenzyl)-4-(2-pyridy1)-1 ,3 ,3-trimethyl-4- piperidinol dihydrochloride In a manner similar to the method described in example 41,. however, applying Z-pyridyl lithium instead of ethyl lithium, the above-mentioned compound is obtained. Yield 68 percent. The dihydrochloride is hygroscopic and melts at 193 196C with decomposition.

EXAMPLE 54 EXAMPLE 55 6-Benzyl-lO-ethyl-7-methyl-7-azaspiro [4.5] decan- 4-ol'hydrochloride In a manner similar to the method described in example 47, 2 g of 6-benzyl-7-methyl-7 azaspiro [4.5] decan-10-one hydrochloride is reacted in 100 ml-of liquid ammonia with acetylene lithium (from 0.5 g of lithium). The reaction product, 6-benzyl-l0-ethinyl-7- methyl-7-azaspiro [4.5] decan-4-ol (2.0 g), is reduced catalytically. Thus 1.8 g of the above-mentioned compound is obtained. It is converted into the hydrochloride which melts at 228 230C. Yield 55 percent.

EXAMPLE 5 6 l-Benzyl-2-methyl-2-azaspiro [5.5] undecan-S-ol picrate To a solution of 0.28 g of l-benzyl-2-methyl-2- azaspiro [5.5] undecan-S-one in 20 ml of absolute ether there is added, with stirring and at room temperature, 0.04 g of lithium aluminum hydride. Afterl45 minutes a small quantity of ammonium chloride and water is added. The ethereal'solution is dried and evaporated in vacuo. The residue does not crystallize. It is converted into the picrate which melts at 206C.

' ple propyl-l,3,3-trimethyl-4-piperidinol,

Yield 94 percent.

EXAMPLE 57 l-Benzyl-3,3-dimethyl-4-ethyl-2-(p-methoxybenzyl)-4- piperidinol hydrochloride in a manner similar to the method described in example 47, 5 g of 1-benzyl-3,3-dimethyl-2-(p-methoxybenzyl)-4-piperidone is reacted with acetylene lithium (prepared from 1 g of lithium in 75 ml of liquid ammonia). The crude product from this reaction is reduced catalytically as described before, leading to the abovementioned compound which is secured as the hydrochloride. Yield 55 percent. Melting point 171 172C with decomposition.

EXAMPLE 58 2-Hydroxy-2,5,9,Q-tetramethyl-6,7-benzomorphan A mixture of 7 g of 2-(p-methoxybenzyl)-1,3,3,4-tetramethyl-4-piperidinol and 70 ml of phosphoric acid (89 percent) is heated at 180 185C during 16 hours. After cooling the reaction mixture is made alkaline with the aid of aqueous ammonia and subsequently extracted with chloroform. The extract is dried over magnesium sulphate and evaporated, leaving a solid residue which after recrystallization from methyl ethyl ketone melts at 157 161C, with sintering at 153C. Yield 48 percent. The hydrochloride melts at 180 183C with decomposition.

EXAMPLE 59 5-Ethyl-2-hydroxy-2,9,9-trimethyl-6,7-benzomorphan In a manner similar to the method described in exam- 58; however, applying 4-ethyl-2-(pmethoxybenzyl)-1,3,3-trimethyl-4-piperidinol the above product is obtained in a 46 percent yield. After recrystallization from methyl ethyl ketone the compound melts at 177 181C.

EXAMPLE 60 5-Ethyl-2'-hydroxy-2,9,9-trimethyl-6,7-benzomorphan A solution of 65 g of 4-ethyl-2-(p-methoxybenzyl)- 1,3,3-trimethyl-4-piperidinol in 700 ml of hydrobromic acid (48 percent) is refluxed during 48 hours. The mixture is diluted with 500 ml of water, filtered and then concentrated in vacuo. The residual sirup is treated with an excess of warm aqueous ammonia. On cooling, a precipitate is formed which is collected by filtration, washed once with water and three times with cold acetone. Yield 40 percent. Melting point 173 177C.

EXAMPLE 61 2-Hydroxy-5-propyl-2,9,9-trimethyl-6,7- benzomorphan hydrochloride In a manner similar to the method described in example 58, however, applying 2-(p-methoxybenzyl)-4- the abovementioned compound is obtained. Yield 24 percent. Melting point 235 245C, with decomposition.

EXAMPLE 62 2'-Hydroxy-S-phenyl-2,9,9-trimethyl-6,7-' benzomorphan In a manner similar to the method described in example 58, however, starting from 2-(p-methoxybenzyl)-4- phenyl-l,3,3-trimethyl-4-piperidi-nol, the above compound is obtained. Yield 49 percent. Melting point 223 230 C.

EXAMPLE 63 2-Hydroxy-5-(Z-pyridyl)-2,9,9-trimethyl-6,7- benzomorphan dihydrobromide In a manner similar to the method described in example 59, however, starting from 2-(p-methoxybenzyl)-4- (2-pyridyl)-1 ,3 ,3-trimethyl-4-piperidinol dihydrochloride, the above-mentioned compound is obtained. It is purified as the dihydrobromide. Melting point 230 233C (decomposition), after recrystallization from isopropanol. Yield percent.

EXAMPLE 64 2,5,9,9-Tetramethyl-6,7-benzomorphan hydrochloride In a manner similar to the method described in example 58, however, starting from 2-benzyl-l,3,3,4-tetramethyl-4-piperidinol, the above compound is obtained. Yield percent. Melting point 220 226C.

EXAMPLE 65 5-Ethyl-2,9,9-trimethyl-6,7-benzomorphan hydrochloride In a manner similar to the method described in example 58, however, starting from 2-benzyl-4-ethyl-l,3,3- trimethylA-piperidinol, the above-mentioned compound is obtained. Yield 62 percent. Melting point 224 226C. 58,

EXAMPLE 66 9,9-Diethyl-2-methyl-6,7benzomorphan ride In a manner similar to the method described in exam hydrochlo- V ple 58, however, starting from 2-benzyl-3,3-diethyl-1- methyl-4-piperidinol, the above-mentioned compound is obtained. Yield 19 percent. Melting point 237 238C.

EXAMPLE 67 morphan separates as an oil, which is extracted from the mixture by shaking with chloroform. Evaporation of the extract leaves the above-mentioned substance. It gives a crystalline oxalate melting at 206 208C. Yield 3 percent.

EXAMPLE 68 5-Ethyl-2-methyl-9,9-tetramethylene-6,7- benzomorphan hydrochloride In a manner similar to the method described in example 58, however, starting from 6-benzyl-10 -ethyl-7-methyl-7-azaspiro [4.5] decan-lO-ol, the above-mentioned compound is obtained. The crude product is purified by chromatography on aluminum oxide with benzene as the eluent and finally secured as the hydrochloride. Melting point 241 244Cwith decomposition. Yield 18 percent.

EXAMPLE 69 2'-Hydroxy-2,5,9,9-tetramethyl-6,7-benzomorphan This substance of which already one method of preparation has been given in example 58, can also be prepared in a different way, which has been described for 9-monosubstituted benzomorphans by Eddy et al., cf. J. Org. Chem. 22, 1370 (1957). The procedure is as follows: A solution of 2,5,9,9-tetramethyl-6,7- benzomorphan in 15 ml of acetic acid is added dropwise to a mixture of 31 ml of nitric acid (100 percent) and 18 ml of acetic acid, which is stirred mechanically and cooled with ice. After completion of the addition which takes 1.5 hours, the mixture is stirred overnight and allowed to come to room temperature, whereupon it is concentrated in vacuo at 55C.

The residue is poured on ice, the solution so obtained is made alkaline with ammonia and subsequently extracted with chloroform. Evaporation of the extract gives an amorphous nitro product which is converted into the crystalline hydrochloride of 2'-nitro-2,5,9,9- tetramethyl-6,7-benzomorphan. Melting point 230-232C, with decomposition. Yield 66 percent. This nitro compound (1.8 g) is dissolved in 50 ml of methanol and reduced catalytically at atmospheric pressure with 0.7 g of 5 percent palladium on barium sulphate as the catalyst.

The catalyst is filtered off and the filtrate evaporated in vacuo leaving a residue which is dissolved in 13 ml of 3 N sulphuric acid. To this solution, while stirred and cooled with ice, 0.45 g of sodium nitrite dissolved in 3 ml of water is added in the course of 30 minutes. Then the reaction mixture is heated 'to 60C whereupon aqueous sulphuric acid (obtained by mixing 7.15ml of concentrated acid with 7.5 ml of water)is added dropwise in the course of 30 minutes. Stirring is continued for an additional hour, during which the temperature is raised gradually to 80C. After cooling by addition of ice the mixture is made alkaline with ammonia and subsequently extracted with chloroform. From this extract the hydroxybenzomorphan derivative can be obtained as described in example 58. After recrystallization from a mixture of I ethanol, acetone and ether the yield amounts to 0.7 g (33 percent). The melting point is 185 188C, with decomposition and is not depressed by admixture with the product obtained according to example 58.

EXAMPLE 7O 9.9-Dimethyl5-ethyl-2'-hydroxy-6,7-benzomorphan A mixture of 13.5 g 'of 5 ethyl-2-hydroxy-2,9,9--

trimethyl-6,7-benzo-morphan and 52 ml of acetic anhydride is heated at 100C for 45 minutes. After cooling, the solution is poured on ice, and after careful basification with 50 percent of aqueous potassium hydroxide, the 0 acetyl derivative is secured by extraction with ether. The product is dissolved in 75 mlof dry chloroform, whereupon in the course of 30 minutes a solution of 8 g of cyanogen bromide in 50 ml of dry chloroform is added dropwise with stirring and at room temperature. Stirring is continued for 3 hours at reflux temperature. Then the solvent is removed by evaporation in vacuo.The residue is refluxed during 18 hours with a mixture of 160 ml of 4 N hydrochloric acid, 160

ml of water and 80 ml of acetic acid. The resulting clearsolution is made alkaline with aqueous ammonia and the oil which separates is taken up in chloroform containing some butanol. The organic solution is dried over magnesium sulphate and concentrated. Stirring the residue with methanol causes the product to crystallize. Yield 59 percent. Melting point 170 174C.

EXAMPLE 71 EXAMPLE 72 5,9,9-Trimethyl-6,7-benzomorphan A solution of 16 g of 2,5,9,9-tetramethyl-6,7- benzomorphan in ml of dry chloroform is treated with cyanogen bromide (11.5 g, dissolved in 75 ml of dry chloroform) as described in example 70. Further processing is also carried out as described in that example, giving the above-mentioned compound in a yield of 53 percent. Melting point 134 137C.

EXAMPLE 73 2'-Hydr0xy-5,9,9-trimethyl-6,7-benzomorphan ln amanner similar to the method described in example 70, however, starting from 2'-hydroxy-2,5,9,9-

tetramethyl-6,7-benzomorphan, the above-mentioned compound is obtained. Yield 42 percent. Melting point 1 10 C.

EXAMPLE 74 9,9-Dimethyl-5-ethyl2'-hydroxy-2-(3-methyl-2- butenyl)-6,7-benzomorphan hydrobromide A mixture of 400 mg of 9,9-dimethyl-5-ethyl-2- hydroxy-6,7-benzomorphan, 300 mg of 3-methyl-2- butenyl-bromide, 250 mg of sodium bicarbonate and 10 ml of dimethylformamide is stirred and heated at 120C for 3.5 hours. Then the mixture is concentrated in vacuo, ether is added, insoluble material is removed by filtration and the filtrate is evaporated in vacuo. The basic residue is converted to the above-mentioned hydrobromide, which, after recrystallization from ethanol/ether melts at 213 -215C. Yield 50 percent.

EXAMPLE 75 2-Al1yl-5-ethyl-2'-hydroxy-9,9-dimethyl'6,7- benzomorphan hydrobromide I In a manner similar to the one described in example 74, however, applying allylbromide, the abovementioned compound is obtained. Yield 55 percent.

Melting point 207 212C, with decomposition.

EXAMPLE 76 2-Allyl-2' hydroxy-5,9,9-trimethyl-6,7-benzomorphan hydrobromide In a manner similar to the method described in example 74, however, starting from 2-hydroxy-5,9,9- trimethyl-6,7-benzomorphan and applying allylbromide, the above-mentioned compound is obtained. Yield 66 percent. Melting point, after recrystallization from ethanol/ether, 220 225C, with decomposition.

EXAMPLE 77 2Cyclopropylmethyl-9,9-dimethyl-5-ethyl-2'-hydroxy- 6,7-benzomorphan hydrobromide In a manner similar to the method described in example 74, however, applying cyclopropylmethylbromide, the above-mentioned compound is obtained. Yield 65 percent. Melting point, after recrystallization from ethanol, 280 283C, with decomposition.

EXAMPLE 78 2-Cyclopropylmethyl-9,9-dimethyl-5-ethyl-2'-hydroxy- 6,7-benzomorphan hydrobromide This compound, which has been mentioned in the preceding example already, may also be prepared via the corresponding cyclopropanecarbonyl compound by means of reduction with lithium aluminium hydride. This procedure precludes the formation of the isomeric N-cyclobutyl derivative, a by-product that may arise when using the method described in example 77.

To a solution of 1 g of 9,9-dimethyl-5-ethyl-2'- hydroxy-6,7-benzomorphan in ml of dry pyridine there is added dropwise, with stirring and cooling with ice, 1.4 ml of cyclopropanecarbonylchloride. The solution is stirred for 16 hours at room temperature and then for 1 hour at 60C. The solution is concentrated by evaporation in vacuo, leaving a residue which is dissolved in ether.

The ethereal solution is washed with 2 N hydrochloric acid and with a saturated aqueous solution of sodium bicarbonate and, after being dried, concentrated in vacuo. The residue consists of the O,N-di(cyclopropylcarbonyl) derivative. A solution of this product in 10 ml of dry tetrahydrofurane is added dropwise to 1.5 g of lithium aluminium hydride suspended in 20 ml of dry tetrahydrofurane, the mixture being stirred and cooled with ice. Stirring is continued at reflux tempera ture, when, after cooling, 50 ml of wet ether and subsequently 10 ml of water are added carefully. The suspension obtained is filtered and the filtrate, after drying over sodium sulphate is evaporated in vacuo. To a solution of the residue in 10 ml of i'sopropanol, hydrogen bromide dissolved in acetic acid is added until the mixture is weakly acid (pH 3). v

On the addition of 20 ml of ether the abovementioned product separates in a crystalline form. Yield 77 percent, Melting point 280C, with decomposition. There is no difference in gaschromatographic behaviour between this product and the compound obtained according to example 77.

EXAMPLE 79 2-Cyclopropylmethyl-5,9,9-trimethyl-6,7- benzomorphan hydrochloride 1n a manner similar to the method described inexample 77, however, starting from 5,9,9-trimethyl-6,7- benzomorphan, the above-mentioned compound is obtained. Yield 59 percent. Melting point 222 227C, with decomposition.

EXAMPLE 8O 2-Cyclopropylmethyl-2-hydroxy-5,9,9-trimethyl-6,7

benzomorphan hydrobromide The cyclopropylmethyl derivative obtained according to example 79 is nitrated according to the method described in example 69. Yield Melting point 93C. Catalytic reduction, followed by diazotation and treatment with hot diluted sulphuric acid in a way similar to the one described in said example, leads to the above-mentioned compound which is isolated as the hydrobromide. After recrystallization from methanol, the melting point is 268 270C, with decomposition. Yield 53 percent.

EXAMPLE 81 9,9-Dimethyl-5-ethyl-2'-hydroxy-2-phenethyl-6,7- benzomorphan hydrobromide To a stirred mixture of 490 mg of 9,9-dimethyl-5- ethyl-2-hydroxy-6,7-benzomorphan, 8 ml of dimethylformamide and 830 mg of potassium carbonate, there is added at room temperature 780 mg of phenacetylchloride within 20 minutes. The mixture is heated during 3 hours at C, cooled, diluted with water and shaken with a mixture of butanol and benzene (2 1). The combined extracts are washed with dilute hydrochloric acid and aqueous sodium bicarbonate successively, dried and evaporated. 1

The residue, consisting of the O,N-di(phenylacetyl) derivative of the starting material, is dissolved in 10 ml of dry tetrahydrofurane whereupon a suspension of 0.5 g of lithium aluminium hydride in 10 ml of dry ether is added to the stirred mixture, at room temperature and in the course of 45 minutes. Stirring is continued at reflux temperature for two hours, whereupon the mixture is cooled with ice and the organo metal complexes are decomposed by the addition of 5 ml of water, followed by 5 ml of 48 percent hydrobromic acid. The organic solvents are removed by evaporation in vacuo leaving an aqueous solution from which a semisolid separates. This is gathered by filtration and dissolved in a small volume of ethanol. From this solution the above substance separates as crystals containing one mole of ethanol. This can be removed by heating at 15 mm'and 120C. Yield 29%. The substance melts partly at C, then resolidifies and finally melts at 222 225C, with decompsition.

EXAMPLE 82 2 -Benzyl-9,9-dimethyl-5-ethyl-2'-hydroxy-6,7-

cooling a solid separates which is gathered and then treated with benzene and aqueous ammonia. The benzene is evaporated and the remaining substance dissolved in a small volume of methanol.

The solution is acidified with hydrogen bromide (dissolved in acetic acid), whereupon methyl ethyl ketone is added and the above compound crystallizes. Yield 51 percent. Melting point 234 236C, with decomposition (after recrystallization from methyl ethyl ketone/- methanol).

2.9 EXAMPLE 83 2-Benzyl-9,9-dimethyl-5-ethyl-2-hydroxy-6,7- benzomorphan hydrobromide In a manner similar to the method described in example 58, however, starting from 1benzyl3,3-dimethyl-4- ethyl-2-(p-methoxybenzyl)-4-piperidinol hydrochloride, prepared according to example 57, the abovementioned substance is obtained. The compound may be purified via the O acetyl derivative (cf. example 67). Melting point 232 235C, with decomposition. The compound is identical with the product obtained according to example 82.

EXAMPLE 84 and 2'-Hydroxy-5,9,9-trimethyl-6,7- benzomorphan The racemic compound (13.9 g, obtained according to example 73) is dissolved in 1 l of a hot aqueous solution of 20 g of ammonium d(+)-3-bromocarnphor-8- sulphonate and 15 ml of 4 N hydrochloric acid. From the solution, on storing in a refrigerator during 16 hours, a salt separates which after recrystallization from water has 01,, 020 (2 percent in ethanol). Yield 4 g.

The mother liquor is concentrated to a volume of 250 ml. After standing at 40C for 1 hour, the oil which has separated, becomes crystalline. This salt is recrystallized from 200 ml of hot water, giving 7.2 g of a substance with 04 2.00( 2% in ethanol).

Additional lots of both salts can be obtained from the mother liquors. Each of the diastereomeric salts is decomposed by shaking with chloroform and 20 percent aqueous ammonia. From the chloroform extracts the enantiomers can be secured by evaporation of the solvent.

The bases are recrystallized from methanol/acetone (l 3). From 3.75 g of the salt with a 0.20 there is obtained 0.75 g of base having oi 2.05 (2 percent in ethanol). The other salt (8.5 g) gives 1.7 g of the base with a 2.10.

EXAMPLE 85 and 9,9-Dimethyl-5-ethyl-2'-hydroxy-6,7- benzomorphan A hot aqueous solution of 1 l of 17.5 g of ammonium d(+)-3-bromocamphor-8-sulphonate, 13 ml of 4 N hydrochloric acid and 13 g of the racemic compound prepared according to example 70, is allowed to cool to room temperature. After 3 hours the crystals which.

have separated are collected. Yield 16.3 g, a 150 (2 percent in ethanol). This crude (l+-) salt is recrystallized from 1 1 of water. Thesolution is cooled in the refrigerator during 16 hours giving coarse crystals of pure (-ll-) salt. Yield 7.2 g, a 1.80". After concentrating the mother liquor to 350 ml, a second crop of' of 4 N hydrochloric acid and 500 ml of hot water. At room temperature a salt separates which is purified by consecutive recrystallization from water and isopropanol giving 6 g of pure salt, 01,, 1.83.

Both enantiomers are secured from their proper salts in the manner described in example 85. Yield 2.1 g with a 1.50 (2 percent in ethanol) from 6.5 g of the salt, and 1.4 g with 04, 1.50 (2 percent in ethanol) from 5 g of the salt. Both enantiomers appear in two modifications which are interconvertable, viz. one crystallizing from methanol in voluminous needles, the other in coarse crystals (also from methanol). Melting point C. The melt is turbid but clarifies at 215C.

' EXAMPLE 86 2-A1lyl-9,9-dimethyl-5-ethyl-2' hydroxy6,7- benzomorphan hydrobromide In a manner similar to the method described in example 75. however, starting from 9,9-dimethyl-5- ethyl-2'-hydroxy-6,7-benzomorphan, the abovementioned enantiomer is obtained. Yield 60 percent. Melting point, after recrystallization from ethanol/ether, 230 240C with decomposition. [a],, 106 (0.9 percent in water)" Specific rotations given in this and the following examples may suffer from errors of: 5.)

EXAMPLE 87 2-Allyl-9,9-dimethyl-5-ethyl-2-hydroxy-6,7- benzomorphan hydrobromide In a manner similar to the method described in example 86, however, starting from the dextrorotatory enantiomer of 9,9-dimethyl-5-ethyl-2'-hydroxy-6,7- benzomorphan, the above-mentioned compound is obtained. Yield 47 percent. Melting point, after recrystallization from ethanol/ether, 230 240C, with decomposition. [ahf 109 (0.8 percent in water).

EXAMPLE 88 2-Cyclopropylmethyl-9,9-dimethyl-5-ethyl-2- hydroxy-6,7-benzomorphan hydrobromide 1n a manner similar to the method described in example 77, however, starting from the dextrorotatory ,enam tiomer of 9,9-dimethyl-5-ethyl-2-hydroxy-6,7- benzomorphan, the above-mentioned compound is obtained. Yield 32 percent. Melting point, after recrystallization from ethanol, 295 297C, with decomposition. [01],, 141 (0.7 percent in dimethylformamide).

In this case, according to gaschromatography, the product appears to be contaminated with 20 percent of an impurity, probably the isomeric cyclobutyl derivative.

EXAMPLE 89 compound is obtained. Yield 72 percent. Melting point 283 285C, with decomposition. [02],, 121 (1 percent in dimethylformamide).

EXAMPLE 90 2-Cyclobutylmethyl-9,9-dimethyl-5-ethyl-2'- hydroxy-6,7-benzomorphan hydrobromide To a solution of 490 mg of 9,9-dimethyl-5-ethyl- 2'-hydroxy-6,7-benzomorphan in 7 ml of dry pyridine, there is added dropwise, with stirring and at room temperature, 700 mg of cyclobutane carbonylchloride. Stirring is continued for 3 hours at room temperature and finally 10 minutes at 40C. The clear, tan reaction mixture is evaporated in vacuo whereupon the residue is shaken with ether and water. The ethereal solution is washed with dilute hydrochloric acid and water, dried and evaporated. A solution of the residue in 25 ml of dry tetrahydrofurane is dropped to a stirred and cooled suspension of 750 mg of lithium aluminium hydride in ml of the same solvent. The mixture is refluxed for 3 hours and subsequently processed as usual. The product is obtained as the hydrobromide which, after recrystallization from ethanol/ether, melts at 285C, with decomposition. Yield 60 percent. [01],, 1 3 1( 1.2% in ,dimethyl-formamide).

EXAMPLE 91 2-Cyclobutylmethyl-9,9-dimethyl-5-ethyl-2'- hydroxy-6,7-benzomorphan hydrobromide This compound is prepared in a manner similar to the one described in the preceding example for the preparation of the dextrorotatory enantiomer. Melting point 288C, with decomposition. Yield 60 percent. [04],, 126 (1.2 percent in dimethylformamide).

EXAMPLE 92 2 '-l-lydroxy-2-( 3-methyl-2-butenyl)-5 ,9 ,9 trimethyl-6,7-benzomorphan hydrobromide From 235 mg of 2'-hydroxy-5,9,9-trimethyl-6,7- benzomorphan, by reaction with 250 mg of 3-methyl-2- butenylbromide and 300 mg of sodium bicarbonate in 50 ml of methyl ethyl ketone (with stirring at room temperature) the above-mentioned compound is pre-' pared. Yeild 40 percent. Melting point, after recrystallization from isopropanol, 180 184C, with decomposition. [a] 125(1.05 percent in water).

EXAMPLE 93 2-Hydroxy-2-(3-methyl-2-butenyl)-5,9,9- trimethyl-6,7-benzomorphan hydrobromide In a manner similar to the one described in the preceding example, however, starting from 2'- hydroxy-S,9,9-trimethyl-6,7-benzomorphan, the

above-mentioned compound is obtained. Melting point I 180 184C, with decomposition. Yield 40 percent. [11],, 135 (1.1 percent in water).

EXAMPLE 94 into the hydrochloride. lt melts at 217 7 222C, with decomposition. Yield 61 percent. [01],, 150 (1.1 percent in water).

EXAMPLE 9,9-Dimethyl-5-ethyl-2'-hydroxy-2-(3-methyl-2- butenyl)-6,7-benzomorphan hydrochloride In a manner similar to the one described in the preceding example, however, starting from the corresponding salt, the above-mentioned compound is obtained in a 58 percent yield. Melting point 217 222C, with decomposition. [0:] 149 (1 percent in water).

EXAMPLE 96 EXAMPLE 97 2-(3-Butenyl)-9,9-dimethyl-5-ethyl-2'-hydroxy-6,7- benzomorphan hydrobromide 1n a manner similar to the one described in example 96, however, applying 4-bromo-l-butene as the alkylating agent, the above-mentioned compound is obtained as the hydrobromide. Melting point 213 215C, with decomposition. Yield 250 mg.

EXAMPLE 98 2-(2-Chloro-allyl)-9,9-dimethyl-5-ethyl-2'-hydroxy- 6,7-benzomorphan hydrochloride A mixture of 500 mg of 9,9-dimethyl-5-ethyl-2'- hydroxy-6,7-benzomorphan, 500 mg of potassium carbonate, 0.3 ml of 2,3-dichloro-l-propene and 30 ml of dimethylformamide is stirred at room temperature for 16 hours, whereupon another 0.2 ml of 2,3-dichloro-lpropene is added and stirring is continued for 4 hours at 40C. Then the mixture is diluted with water and extracted with petroleum ether. Evaporation of the extract gives a residue which is heated with l N hydrochloric acid for 2 hours, in order to hydrolyse some 0- alkylation product. After basification with an excess of aqueous ammonia and extraction with benzene, the above-mentioned compound is obtained by evaporation of the extract. Conversion into the hydrochloride gives a product melting at 230 232C, with decomposition. Yield 100 mg.

EXAMPLE 99 9,9-Dimethyl-5-ethy1-2'-hydroxy-2-propargyl-6,7- benzomorphan hydrochloride in a manner similar to the one described in example 98, however, using propargyl chloride as the alkylating agent, the above-mentioned compound is obtained. Melting point 218 220C, with decomposition. Yield 180 mg.

EXAMPLE 100 2-( 2-Cyclohexenl -yl )-9,9-dimethyl-5-ethyl-2 hydroxy-6,7-benzomorphan By reaction of 245 mg of 9,9-dimethyl -ethyl-2'- hydroxy-6,7-benzomorphan with 200 mg of 3-bromocyclohexene and 200 mg of potassium carbonate in 500 ml of methyl ethyl ketone, the above-mentioned compound is obtained. Yield 61 percent. Melting point 122 125C, after recrystallization from petroleum ether.

EXAMPLE 101 2-( 2-Cyclohexyliden-ethyl)-9,9-dimethyl 5-ethyl-2 hydroxy-6,7-benzomorphan hydrobromide In a manner similar to the one described in example 100, however, applying (2-bromo-ethylidene)- cyclohexane, the above-mentioned compound is obtained. Yield 50 percent. Melting point 205 208C, with decomposition.

EXAMPLE 102 2-( l -Cyclohexen-1-yl-methyl)-9,9-dimethyl-5-ethyl-2 hydroxy-6,7-benzomorphan hydrochloride v ln-a manner similar to the methoddescribed in example 100, however, applying l-chloromethylcyclohexene, the above compound is obtained. Yield 45 percent. Melting point 230 233C, with decomposition.

EXAMPLE 103 EXAMPLE- 105 5-Ethyl-2'-nicotinoyloxy-2,9,9-trimethyl-6,7- benzomorphan oxalate This compound is prepared by reaction of 518 mg of 5-ethyl-2'-hydroxy-2,9,9-trimethyl-6,7-benzomorphan with 425 mg of nicotinoyl chloride in 20 ml of dry pyridine during 16 hours at room temperature. After evaporation of the solvent in vacuo, the residue is shaken with petroleum ether and aqueous ammonia. The petroleum ether solution is fractionated by chromatography on aluminium oxide. The product is secured as the acid oxalate, which crystallizes with 2 moles of 1 water. Yield 55 percent. Melting point 202 204C, with decomposition.

EXAMPLE 106 5-Ethyl-2"methoxymethoxy-2,9,9-trimethyl-6,7- benzomorphan oxalate A mixture of 2 g of 5-ethyl-2-hydroxy-2,9,9- trimethyl-6,7-benzomorphan, 20 ml of 1,2- dimethoxyethane and 240 mg of sodium hydride (as a percent suspension in oil) is heated at 80C for 2 EXAMPLE 107 5-Ethyl-2-methoxy-2,9,9-trimethyl-6,7- benzomorphan oxalate To a stirred solution of 1 g of 5-ethyl-2-hydroxy 2,9,9-trimethyl-6,7-benzomorphan and-2 g of potassium hydroxyde in 50 ml of methanol and 3 ml of water, there is added, at room temperature and within 2 hours, a solution of 2.15 g of N-nitroso-N-methyl-p-toluene-sulphonamide in 20 ml of ether. After continued stirring (1 hour), another quantity of 2.15 g of the nitroso amide is added in the same way.

After 16 hours the suspension is filtered, whereupon the filtrate is acidified to pH 3 with 4 N sulphuric acid in order to decompose the excess of diazomethane. After concentration of the mixture in vacuo it is shaken with petroleum ether and aqueous ammonia. Evaporation of the solvent leaves the substance as a base which benzomorphan oxalate In a manner similar to the method described in example 106, however, applying benzoyl chloride instead of chloromethyl methyl ether, the above-mentioned compound is obtained as the acid oxalate. Melting point 223 225C, with decomposition. Yield 73 percent.

EXAMPLE 109 2-(3-Bromo-3-methyl-butyl)-9,9-dimethyl-5-ethyl- 2'-hydroxy-6,7-benzomorphan hydrobromide A mixture of 250 mg of (-)9,9-dimethyl-5-ethyl-2- hydroxy-6,7-benzomorphan, 30 ml of methanol, 300 mg of N-ethyl diisopropylamine and 0.3 ml of 3-methyl-2-butenylbromide is stirred at room temperature for 16 hours. After removal of the solvent by evaporation, the residue is shaken with chloroform and am-' m'onia. The chloroform solution is evaporated to leave a base which is dissolved in a small quantity of isopropanol and then treated at C with concentrated hydrobromic acid. The mixture is evaporated to dryness and the solid thus obtained is recrystallized from isopropanol/acetone. The above compound melts at C, with decomposition. Yield 170 mg. [111 82 (1 percent in methanol).

Tests were conducted with respect to the pharmacological properties of various 6,7-benzomorphans according to this invention which are included within general formula 11 above, and in which the substituents R, R R and R are as indicated in the below Table A. The tests conducted were as follows:

Tail Withdrawal Test In Rats The analgesic potency of the tested compounds was determined by the so-called tail withdrawal test in male rats having a body weight of 250 i 10 g. substantially 35 in accordance with the standard procedures described by Janssen P.A.J., Niemegeers C..l.E. and Dony .I.G.H.; Arzneim-Forsch, 13, 502 (1963). The test procedures were substantially as described, with the exceptions blockage of the corneal and pinna reflexes resulting from the administration of high doses of fentanyl, male Wistar rats were given a subcutaneous injection of 0.63 mg/kg body weight of fentanyl to induce the described that measurements were made more frequently, the phenomena. 30 minutes after the fentanyl dose, the cut-off time was reduced from 15 seconds to secsame animals received intravenous injections of the onds, and the results were rated according to three difidentified test compounds and of Nalorphine and Penferent levels of analgesia, defined as follows: tazocine for comparison purposes. Table A indicates a. Moderate analgesia (MA. on Table A) the tail the lowest active'dose, in mg/kg body weight, exhibitwithdrawal reaction time is 6 and 10 seconds. 10 ing nalorphine-like properties, that is, capable of immeb. Pronounced analgesia (P.A. on Table A) no tail diately reversing the mentioned phenomena induced by withdrawal response over a reaction time 10 secthe dosage of fentanyl. onds,.but slight movements of the tail in the warm water Cup writhing Test In Rats 0. Surgical analgesia (S.A. on Table A) no tail Female Wistar rats were injected with 1/2 ml. of a l withdrawal response over a reaction time 10 seepercent-solution of acetic acid LP. and the number of onds, and no movements or reaction f the t il, writhings during the 60 minutes following the injection Table A gives the dosages, in mg./kg of body weight, were noted. In control animals, the mean number of administered subcutaneously that constitute the ED writhings was 100 during the 60 minutes following the values and confidence limits for each of th defi d injection of acetic acid solution. The various test comcompounds to achieve the above defined levels of analpounds identified on Table A, and also Nalorphine and gesia (M.A., P.A. and S.A.). For purposes of compari- Pentazocine for the purposes of comparison, were adson, Table A also gives the corresponding values for ministered subcutaneously minutes prior to the stan- Nalorphine and Pentazocine. dard injection of acetic acid. Table A gives, for each 25 test compound, the lowest active dosage, in mg/kg Nalorphme'hke Acnv'ty In Rats body weight, that reduced the number of writhings by In order to test the Nalorphine-like activity of the at least one-half, that is 50. writhings in the 60 mintested compounds, that is, the potency of such comutes following the acetic acid injection.

TABLE A Nalor- Tail withdrawal test phinelike Wrlthing R; R R M.A. RA. S.A. activity t0 0H CH3 CH3 0. 0. 0H CH5 CH5 0.08 0.10 OH CH: CH: 0.12 0. 16 OH CH: CH: 0.08 0.16 H CH5 CH1 10 10 H C2H5 C2115 2. 5 2. 5 OH (CH2)4 0.31 0.31 H (.CH215 10 10 OH CH: CH: 1.25 3.5 0H CH5 CH5 25 25 0. 04 0. 0H CH3 CH1 -2. 5 2. 5 0. 02 0. OH CH5 CH5 25 25 0. 02 20. OH CH: CH; 1.25 2.5 25 0. 02 0.16 0H CH3 CH5 0. 25 0.25 0.50 OH CH; CH; 10 10 10 25 0H CH5 CH1 25 25 25 0.01 010 OH CH3 CH5 25 25 25 0. 16 0H CH1 CH1 25 25 25 015 OH CH5 CH5 25 25 25 0.01 010 0H CH5 CH5 -25 25 25 0. 5 OH CH3 CH5 0.31 -25 25 4 0H CH; CH: 25 25 25 OH CH5 CH1 -2. 5 2. 5 2. 5 0H CH1 CH1 10 10 10 OH CH1 CH1 0.31 0.31 2.5 0H CH5 CH5 10 10 10 0H CH: CH: 0.16 0.31 5. 0 OH CH3 CH1 10 10 10 OH CH: CH3 10 10 10 OH CH; CH; 25 25 25 CzHs OH CH: CH: HBr 2.5 25 2.5 063 2.5 CH5CH= 01H, 0H CH5 CH5 H01 210 10 10 010 25 CH2- CH5 01H, OCOCH; CH; CH; 055001 0.02 0.04 CH: CzH OCOC 2H5 CH1 CH3 CzH204 0- 04 0. 08 CH3 C2H5 OCOC5H3N CH3 CH3 CzHzOi 0.04 0.08 CH5 CQHS OCHQOCH; CH3 CH5 0511201 1.25 2.5 CH3 CeHs OCH: CH3 CH5 CzHzOt 0.31 1.25 CH3 CzHs OCOCeHs CH3 CH3 0211204 0.08 0.08 CH2CHz-C(CH3); B 2H5 CH3 CH3 HBX 0.31 1.25 Nalorphine 1 20 40 Pentazocine 5. 0 40 pounds in reversing the respiratory depression, loss of righting reflex, muscular rigidity, surgical analgesia and What is claimed is: l. A compound selected from the group consisting of substituted 6,7-benzomorphans having the formula in which both substituents R are selected from the class consisting of methyl and ethyl groups and groups forming tetramethylene when taken together with the carbon atom to which they are bonded, R, is selected from the class consisting of hydrogen atom, alkyl, haloalkyl and alkenyl groups containing up to seven carbon atoms, haloalkenyl and alkinyl groups containing up to four carbon atoms, phenethyl and benzyl groups, cycloalkenyl and cycloalkylidene-alkyl groups containing up to eight carbon atoms and cycloalkylalkyl and cycloalkenylalkyl groups containing up to seven carbon atoms, R is selected from the class consisting of alkyl groups containing up to three carbon atoms and phenyl and-2-pyridyl'groups, and R is selected'from the class consisting of hydrogen atom, hydroxy groups, alkoxy groups containing up to two carbon atoms, methoxymethoxy groups, nicotinoyloxy groups, and lower al- -kanoyloxy and benzoyloxy groups; 

2. A compound according to claim 1, in which each of said substituents R is a methyl group.
 3. A compound according to claim 2, in which R1 is selected from the class consisting of methyl, allyl, 3-methyl-2-butenyl, cyclopropylmethyl, cyclobutylmethyl and phenethyl groups.
 4. A compound according to claim 1, in which R1 is selected from the class consisting of methyl, allyl, 3-methyl-2-butenyl, cyclopropylmethyl, cyclobutylmethyl and phenethyl groups. 